Analyzing Joshimath's sinking: causes, consequences, and future prospects with remote sensing techniques.

Area of Science:

• Geosciences and Remote Sensing
• Natural Hazard Monitoring
• Earth Surface Dynamics

Background:

• The Himalayas are prone to natural disasters, including land deformation, earthquakes, and landslides.
• Joshimath town recently experienced severe land subsidence, causing widespread damage to infrastructure and posing risks to residents.

Purpose of the Study:

• To monitor and analyze land deformation in the Joshimath region using advanced remote sensing techniques.
• To identify the primary causative factors contributing to the observed land subsidence.
• To provide recommendations for future development policies in vulnerable Himalayan regions.

Main Methods:

• Utilized Persistent Scatterer Synthetic Aperture Radar Interferometry (PSInSAR) with multi-temporal Sentinel-1 datasets to calculate land deformation velocity (2022-2023).
• Conducted feature tracking land displacement analysis using high-resolution Planet datasets.
• Assessed ground conditions in critical areas using Unmanned Aerial Vehicle (UAV) datasets.

Main Results:

• Land deformation velocity in Joshimath (2022-2023) ranged from -89.326 to +94.46 mm/year, with the highest rates observed in the north-western part.
• Maximum land subsidence occurred around Singhdwar (+60.45 to +94.46 mm/year), while other areas showed moderate to high subsidence or localized expansion.
• Land deformation was significantly higher in 2022-2023 compared to previous periods (2016-2017, 2018-2019, 2020-2021).

Conclusions:

• Land deformation in Joshimath is primarily driven by uncontrolled anthropogenic activities, infrastructural development, and inadequate drainage systems.
• The findings highlight the urgent need for revised development policies to mitigate risks in susceptible Himalayan regions.
• Integrated remote sensing and UAV-based assessments are crucial for understanding and managing land deformation hazards.